The towering reality star has not been asked to return as co-host of the high-profile Fox singing competition, sources tell The Post.

“They are asking Mario [Lopez] to come back, but not Khloe,” an insider confirms.

Kardashian, 28, came to the show with no television hosting experience and often appeared nervous and unprepared on camera.

The Huffington Post went so far as to suggeste that the “awkward” pair were secretly being paid off by rival singing show “The Voice.”

“I am sure there was a big percentage of Khloe’s fans who followed her to ‘X Factor.’” said LA hosting expert Marki Costello, who has provided on-camera coaching for “Voice” judge Cee Lo Green among others.

“But at the end of the day, when she doesn’t know what she is doing, are you helping your show or hurting it?

“It was really hard for me to watch Mario with her,” she said. “It made me, as a viewer, almost uncomfortable.”

Kardashian’s exit follows the departure last month of judge Britney Spears — who received lukewarm reviews at best during her debut last season.

Judge L.A. Reid also bailed in December, saying he needed to focus more on his day job as head of Epic Records.

Now Fox and the show’s creator, Simon Cowell, are scrambling to rebuild the wildly hyped series which a News Corp. executive called “a disappointment” during a conference call with investors this month. (News Corp. owns Fox, as well as The Post.)

Meanwhile, Brit singer Cheryl Cole, who was unceremoniously dumped as a judge last year, is in talks to return to the show — possibly as part of a judging panel that would be comprised of Cowell and three younger women.

Cole — who was a judge on the U.K. version of “X Factor” — filed a $2.3 million lawsuit against the show last December, claiming the show still owed her money after replacing her just a few weeks into the first season.

Her return could be part of a settlement.

Cowell says he regretted letting Cole go last year.

“I had to apologize for the way it was handled,” he told reporters later.

It may also signal that the show — which invested $15 million in Spears last season only to see ratings plunge by 20 percent during the season — is trimming its talent budget.

An X Factor spokesperson said “The producers have not yet made the talent decisions for this year.”